Update to tvheadend 4.2.1 stable

Dockerfile

@@ -4,6 +4,7 @@ MAINTAINER saarg
 # package version
 ARG ARGTABLE_VER="2.13"
 ARG FFMPEG_VER="ffmpeg"
+ARG TVH_VER="v4.2.1"
 ARG TZ="Europe/Oslo"
 ARG XMLTV_VER="0.5.69"
 
@@ -144,6 +145,7 @@ RUN \
 # build tvheadend
  git clone https://github.com/tvheadend/tvheadend.git /tmp/tvheadend && \
  cd /tmp/tvheadend && \
+ git checkout "${TVH_VER}" && \
  ./configure \
 	--disable-ffmpeg_static \
 	--disable-hdhomerun_static \

README.md

@@ -46,7 +46,8 @@ Add one of the tags, if required, to the linuxserver/tvheadend line of the run/c
 
 #### Tags
 
-+ **stable-4.0.9** : latest stable version.
++ **stable-4.2.1** : latest stable version.
++ **stable-4.0.9** : old stable version. Will not be updated anymore!
 
 #### Host vs. Bridge
 
@@ -151,6 +152,7 @@ You need to enable minimum advanced view level to see the picons options.
 
 ## Versions
 
++ **01.05.2017:** Update to tvheadend 4.2.1 stable.
 + **18.04.2017:** Use repo version of gnu-libiconv rather than compiling.
 + **09.04.2017:** Chain cpanm installs in one block and use --installdeps.
 + **09.02.2017:** Perl changes, add picons file to gitignore and update XMLTV to 0.5.69.